This invention relates to a fuel injection system for an internal combustion engine and more particularly to an improved injection arrangement for improving fuel consumption and reducing hydrocarbon (HC) emissions.
The advantages of direct cylinder fuel injection are well known. However, one disadvantage with direct cylinder fuel injection is that under some running conditions, it may actually deteriorate fuel economy. The- reason for this is due to the overlap cycle of the opening of the exhaust port and the period of fuel injection. Frequently, the flow of the charge in the combustion chamber can cause a portion of the directly injected fuel to be swept through the exhaust port during such time as fuel is being injected and the exhaust port is open thus reducing fuel economy and increasing HC emissions.
The aforenoted problem is particularly acute in conjunction with two cycle engines due to the fact that fuel injection and exhaust port openings frequently have substantial overlap. Although direct cylinder injection has been proposed as a means of improving the fuel economy in a two cycle engine, the problem of having injected fuel pass directly out the exhaust port is a particular problem in direct cylinder injected two cycle engines.
It is, therefore, a principal object of this invention to provide an engine and method of operating it embodying fuel injection and insuring that fuel will not pass out of the exhaust port during the time when the exhaust port is open.
It is a further object of this invention to provide an improved two cycle direct injected engine and method of operating it wherein fuel economy can be improved.
It is a further object of this invention to provide an improved two cycle engine and injection system wherein injected fuel will not pass out of the exhaust port.